In early 1962, Attorney General Robert Kennedy approved a request from FBI Director J. Edgar Hoover to install wiretaps on the home and office of a New York City-based lawyer named Stanley David Levison. According to FBI informants, Levison had been an influential member of the Communist Party of the United States of America (CPUSA) as late as 1956. They believed he was now wielding influence in a different way—as a top adviser to the nation’s most prominent civil rights leader, Dr. Martin Luther King Jr.

As King’s fame and stature grew over the next several years, the FBI intensified its surveillance of him under its domestic counterintelligence program, COINTELPRO, arguing it was a matter of national security. While the bureau’s relentless scrutiny of King failed to reveal any communist leanings, it did turn up evidence of King’s extramarital affairs. Hoover and his agents then tried to leverage that information not only to discredit and weaken King as a leader of the civil rights movement, but to blackmail him into taking his own life.

Hoover built his nearly five-decade FBI career on fighting the perceived threat of communism. His determined efforts to root out suspected sympathizers during the first Red Scare helped cement his meteoric rise to lead the FBI in 1924, at just 29 years old. With the dawn of the Cold War, he rededicated his efforts to investigate communists and others whom he considered potential enemies of the United States—seeing red in, among other places, Hollywood’s labor unions and creative class. By the time of his death in 1972, Hoover had amassed confidential files on an impressive array of public figures, from Charlie Chaplin to Muhammad Ali to Eleanor Roosevelt.

Because the CPUSA had supported greater civil rights for Black Americans as far back as the 1930s, Hoover was not alone in viewing the emerging civil rights movement of the 1950s as susceptible to communist influence. The FBI first took notice of King in 1955, when the young minister played a leading role in the Montgomery bus boycott.

For his part, King preached actively against communism from the early 1950s onward, arguing that it was fundamentally incompatible with Christianity. Despite this, he was forced to defend himself against allegations that he was a communist throughout his career.

King and Levison met in 1956 through Bayard Rustin, another civil rights leader. Levinson ultimately became one of King’s closest advisers, helping the movement with fundraising, ghostwriting speeches and more, including editing and securing a publishing deal for King’s first book, Stride Toward Freedom.

As King biographer David Garrow wrote in his 1981 book, The FBI and Martin Luther King Jr., valued informants provided the FBI with credible reports about Levison’s role as a top CPUSA financier from the mid-1940s to 1956. Though Levison reportedly disappeared from party affairs around the time he met King, Hoover remained convinced he was still involved. His arguments were enough to convince Robert Kennedy to authorize wiretapping Levison’s home and office within weeks of learning of his connection with King.

Members of the Kennedy administration—including President John F. Kennedy—later warned King personally to distance himself from Levison and another suspected Communist, Jack O’Dell, who worked for King’s Southern Christian Leadership Conference (SCLC). After King fired O’Dell in 1963 but continued to work with Levison through an intermediary, Clarence Jones, Robert Kennedy authorized the wiretapping of Jones’s home and offices as well.

In August 1963, King delivered his now-iconic “I Have a Dream'' speech from the steps of the Lincoln Memorial during the March on Washington. His growing prominence brought increasing scrutiny from the FBI. “We must mark [King] now...as the most dangerous Negro of the future of this Nation from the standpoint of communism, the Negro and National security,” wrote William Sullivan, head of the bureau’s domestic intelligence division, on August 30.

In October 1963, Robert Kennedy authorized the installation of wiretaps in King’s Atlanta home and the SCLC offices, with the understanding that the FBI was continuing to investigate his suspected communist ties. Within months, however, the bureau expanded its surveillance of King, placing bugs and wiretaps in the hotel rooms he visited. The expansion reflected the FBI’s new objective: collecting evidence of King’s extramarital activities in order to sully his reputation and weaken him as leader of the civil rights movement.

Even as King was scoring historic victories in 1964—including passage of the Civil Rights Act and the Nobel Peace Prize—his public criticism of the FBI and its failure to act on civil rights violations in the South brought him into direct public conflict with Hoover.

At a press conference in November 1964, Hoover called King the “most notorious liar in the country,” prompting King to defend himself in the press and seek a meeting at the director’s office to defuse tensions. After the two men met for more than an hour in Hoover’s office in early December, King told reporters he and Hoover had enjoyed a “quite amicable discussion.” His aide Andrew Young, who was present at the meeting, later recalled that there was “not even an attitude of hostility.”

Meanwhile, Hoover’s FBI took one of its most shocking actions toward King. A few days after Hoover’s press conference, Sullivan drafted an anonymous letter to the civil rights leader, suggesting intimate knowledge of his alleged sexual activities. Through agents, he sent the letter to King in Atlanta, along with a tape recording supposedly documenting some of those extramarital encounters.

As historian Beverly Gage has written, King and his close associates believed the letter was suggesting he should kill himself. It set a deadline of 34 days “before your filthy, abnormal fraudulent self is bared to the nation” and concluded by saying “There is only one thing left for you to do.” They also (correctly) assumed that the source of the letter, and the tape, was the FBI. Senate investigators revealed in 1975 that a draft of the letter was found in Sullivan’s files, though he denied any knowledge of it and suggested it had been Hoover’s work.

Though the FBI stopped wiretapping King’s home in April 1965 and his office the following year—it continued investigating him all the way up until his assassination in Memphis on April 4, 1968. The extent of the FBI’s campaign attempt to use King’s personal life against him, including the infamous “suicide letter,” as it became known, first came to light in 1976, four years after Hoover’s death, with the damning report of the Senate Select Committee to Study Governmental Operations With Respect to Intelligence Activities, popularly known as the Church Committee.

“The FBI has stated that at no time did it have any evidence that Dr. King himself was a communist or connected with the Communist Party,” the Church Committee reported in a section dedicated to the King investigation. “Rather than trying to discredit the alleged communists it believed were attempting to influence Dr. King, the Bureau adopted the curious tactic of trying to discredit the supposed target of Communist Party interest—Dr. King himself.”

In 1977, King’s former assistant Bernard Lee sued the FBI for damages relating to the bureau’s surveillance of King. A federal judge in the case denied Lee’s request that surveillance tapes and transcripts be destroyed, instead ordering the FBI to turn them over to the National Archives, where they remain sealed until 2027.